(1) Field of the Invention
The invention relates to a seat back unit, and more particularly to a seat back unit having a herringbone-shaped structure formed by a vertical arch section of a backrest member and several transversal curved sections, and the herringbone-shaped structure conforms to the profile variation of the human body and provides different supporting forces according to the weights of different parts of the body.
(2) Description of the Prior Art
The people are seated at most of time in the daily life and the working period. Therefore, whether the chair is safe and comfortable has become the primary requirement of the people.
Although the existing chair has the seat back, the seat back has the stiff line profile, cannot satisfy the requirement of the body profile and cannot provide the independent supports for various parts of the body. In addition, the supporting force also cannot be adjusted. When a person is seated for a long time, the body tends to get tired. Because the supporting forces cannot be adjusted, the supporting forces applied to different parts of the body are different. After a long time, some parts of the body may feel uncomfortable, lack of energy, have aches and encounter the chronic back problem.